Blu-ray FAQ - Blu-ray vs HD-DVD

1.Is Blu-ray the same thing as HD-DVD?


No, HD-DVD (previously known as AOD) is the name of a competing next-generation optical disc format developed by Toshiba and NEC. The format is quite different from Blu-ray, but also relies heavily on blue-laser technology to achieve a higher storage capacity. The format is being developed within the DVD Forum as a possible successor to the current DVD technology.


2.What benefits does Blu-ray offer compared to HD-DVD?


Although both Blu-ray and HD-DVD are similar in many aspects, there are some important differences between them.

The first is capacity. Because Blu-ray utilizes a lens with a greater numerical aperture (NA) than HD-DVD, the laser spot can be focused with greater precision to fit more data on the same size disc. This allows Blu-ray to hold 25GB per layer (50GB on a dual-layer disc), whereas HD-DVD can only hold 15GB per layer (30GB on a dual-layer disc). Blu-ray has also adopted a higher data transfer rate for video and audio (54Mbps vs 36.55Mbps). The greater capacity and data transfer rates for Blu-ray will allow the movie studios to release their movies with higher quality video and audio than the HD-DVD format.

The second is content. The Blu-ray format has received broad support from the major movie studios as a successor to today's DVD format. Seven of the eight major movie studios (Warner, Paramount, Fox, Disney, Sony, MGM and Lionsgate) have released titles for Blu-ray, whereas HD-DVD only has support from two major movie studios (Paramount and Universal). This is an important difference because some of the studios might only support one of the formats, so you won't be able to get your favorite movies in the other format. Choosing the format with the most content support minimizes this risk.

The third is hardware support. The Blu-ray format has broad support from the world's leading consumer electronics, personal computer and media manufacturers, including Sony, Panasonic, Philips, Samsung, Pioneer, Sharp, JVC, Hitachi, Mitsubishi, TDK, Thomson, LG, Apple, HP and Dell. The Blu-ray format will also be supported in the next-generation PlayStation 3 (PS3) video game console. This means that you will have a lot of choice when it comes to players and hardware. The HD-DVD format has far fewer supporters, so the amount of players and hardware will be very limited. Currently, Toshiba is the only company offering a stand-alone HD-DVD player.


3.What is the difference between Blu-ray and HD-DVD?

Parameters	Blu-ray	HD-DVD
Storage capacity	25GB (single-layer) 50GB (dual-layer)	15GB (single-layer) 30GB (dual-layer)
Laser wavelength	405nm (blue laser)	405nm (blue laser)
Numerical aperture (NA)	0.85	0.65
Disc diameter Disc thickness	120mm 1.2mm	120mm 1.2mm
Protection layer Hard coating	0.1mm Yes	0.6mm No
Track pitch	0.32µm	0.40µm
Data transfer rate (data) Data transfer rate (video/audio)	36.0Mbps (1x) 54.0Mbps (1.5x)	36.55Mbps (1x) 36.55Mbps (1x)
Video resolution (max) Video bit rate (max)	1920×1080 (1080p) 40.0Mbps	1920×1080 (1080p) 28.0Mbps
Video codecs	MPEG-2 MPEG-4 AVC SMPTE VC-1	MPEG-2 MPEG-4 AVC SMPTE VC-1
Audio codecs	Linear PCM Dolby Digital Dolby Digital Plus Dolby TrueHD DTS Digital Surround DTS-HD	Linear PCM Dolby Digital Dolby Digital Plus Dolby TrueHD DTS Digital Surround DTS-HD
Interactivity	BD-J	HDi